Further studies on acetyl-CoA carboxylase kinase and phosphatase: We still have to isolate the kinase specific to acetyl-Coa carboxylase. With our isolated phosphatase, we hope to produce rabbit-antibody to the enzyme, so that we can determine whether this phosphatase is immunologically similar to other nonspecific phosphatases. Regulation of covalent phosphorylation by the adenylate energy charge: To establish this regulatory mechanism, it is essential to demonstrate the distinct binding site for AMP (regulatory site) on the carboxylase. Affinity binding and fluorescent changes in association with AMP binding are being studied. Generality of regulation of covalent phosphorylation in other covalently modificable enzymes: Glycogen synthase and pyruvate kinase will be examined to determine whether covalent phosphorylation is regulated in a manner similar to the acetyl-CoA carboxylase system. Isolated Hepatocyte System: To examine the physiological significance of CoA activation of the carboxylase, and the regulation of covalent phosphorylation of the carboxylase by the adenylate energy charge, we have prepared an isolated hepatocyte system. Using this system, we hope to examine changes in the metabolites in the mitochondrial and cytosol fractions under different physiological conditions.